Sensory devices based on amplified fluorescence quenching of solid-state conjugated polymer films can be highly sensitive, due to the amplification that arises from delocalized excitons sampling many potential binding sites within one excited state lifetime. Previous work has demonstrated highly sensitive detection schemes using these amplifying fluorescent polymers for a number of analytes in solution and vapor phase, as described in U.S. Publication No. 2003/0178607. In many cases, the transduction mechanism is photoinduced charge transfer (PICT) from a polymer donor to an analyte that binds via a tight pi-complex to the conjugated polymer.
In the detection of biological molecules, the sample may often contain various biological species in a complex, aqueous environment. Many conjugated polymers have been shown to exhibit nonspecific interactions with such species via, for example, electrostatic interactions, making it difficult to design a sensor that selectively interacts with a particular biological analyte of interest, such a protein.
Accordingly, improved methods are needed.